National Council of Teachers of Mathematics
Nctm: Illuminations: Computing Pi
This resource investigates approximating the value of pi through the calculation of perimeters of inscribed or circumscribed polygons. The interactive tool allows learners to examine and compare both methods.
Texas Instruments
Texas Instruments: Approximation of Pi Using an Area Model
Students will approximate pi by setting up trigonometric ratios and calculating the areas of regular polygons inscribed within and circumscribed about a circle.